背景回顾：Seed size is a major factor determining crop yields that is controlled through the coordinated development of maternal and zygotic tissues. 

主要发现：Here, we identified Arabidopsis MATERNAL EFFECT EMBRYO ARREST45 (MEE45) as a B3 transcription factor that controls cell proliferation and maternally regulates seed size through its transcriptional activation of AINTEGUMENTA (ANT) and its downstream control of auxin biosynthesis in the ovule integument. 

结果1-MEE45敲除、过表达及下游基因ANT鉴定：After characterizing reduced seed and organ size phenotypes in mee45 mutants and finding that overexpression of MEE45 causes oversized seeds, we discovered that the MEE45 protein can bind to the promoter region of the ANT locus and positively regulate its transcription. 

结果2-ANT下游激活生长素合成：ANT in-turn activates expression of auxin biosynthetic genes (e.g., YUCCA4) in the ovule integument. 

结论：Our results thus illustrate mechanisms underlying maternal tissue-mediated regulation of seed size and suggest that MEE45 and its downstream components can be harnessed to develop higher yielding crop varieties.

 摘 要 

种子大小是决定作物产量的主要因素，在母本和合子组织的协调发育过程中受到严格控制。本文中，作者鉴定了拟南芥MEE45做为一个B3转录因子，通过转录激活胚珠珠被中ANT基因的表达及其下游生长素合成的控制，调控细胞增殖，并母系调控种子大小。作者发现mee45突变体的种子和器官尺寸均减小，而MEE45过表达则导致种子增大。作者发现，MEE45蛋白能够结合到ANT位点的启动子区，正向调控ANT基因的转录。然后，ANT会激活胚珠珠被中YUC4等生长素合成基因的表达。本文的研究揭示了一个母本组织调控种子大小的分子机制，阐明了MEE45及其下游组分可以用来培育高产作物品种。

 通讯作者 

** 苏英华 **